Several methods have been known which produce propylene from an olefins-containing hydrocarbon raw material by using a zeolite-containing catalyst. Examples known as zeolite-containing catalysts for use in the production of propylene from olefins include a catalyst in which Ag is contained in an intermediate pore size zeolite that substantially does not contain protons and a catalyst in which the silica/alumina (SiO2/Al2O3) molar ratio thereof falls within a range from 200 to 5000.
Although the term “olefins” covers a broad concept, the “olefins” that have hitherto been used as raw materials for the production of propylene are limited to the olefins having four or more carbon atoms. However, some documents describe that raw materials other than the aforementioned olefins can be used.
For example, Japanese Patent Laid-Open No. 2001-31979 describes “a method including contacting a hydrocarbon feedstock containing one or more olefinic components of C4 or greater with a crystalline silicate catalyst to produce an effluent having a second composition of one or more olefinic components of C3 or greater, the feedstock and the effluent having substantially the same olefin content” (claim 1), and also describes that “preferably, the ethylene comprises from 0.1 to 50 wt % of the hydrocarbon feedstock” (paragraph 0028).
Japanese Patent Laid-Open No. 2006-335730 describes a method for producing propylene from ethylene and methanol and/or dimethyl ether.
Japanese Patent Laid-Open No. 2007-191444 describes a method for producing propylene from ethanol (that is, ethylene and water generated via a dehydration reaction) with, as a solid acid catalyst, an H-ZSM5 zeolite in which metal ions are introduced or a phosphate zeolite such as SAPO-34.